Translucent element and locking means therefor



T. VEITCH Jan 6, 1942 TRANSLUCENT ELEMENT AND LOCKING MEANS THEREFOR Filed Aug. 1, 1959 14 III 17 5110c 11 To: W

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Patented Jan. 6, 1942 UNITED STATES PATENT o F CE TRAN SLUCENT ELEMENT AND LOCKIN G MEANS THEREFOR Thomas Veitch, Torresdale, Pa.

. Application August 1, 1939, Serial No. 287,706

' 3 Claims. (CL 40-433) This invention relates to illuminated signs,

panels and indicators of the type wherein a translucent member is placed in an opening in an opaque panel to transmit light from a source behind said panel. More particularly this invention pertains to the formation of the translucent member and the cooperating means for locking it permanently in place in the face of a sign, panel or other member.

The present invention is adaptable to any installation Where it is desired to have light shine through a jewel-like member for outlining or accentuating letters, words or designs, for serving as an indicating, signal or border light and other similar purposes.

In the manufacture of illuminated signs, which is herein described as one application of the invention, it may be necessary to install a very large number, even several hundred, separate translucent members in a single sign. The labor involved is therefore an important economic factor. It is essential, too, that the translucent members be fastened into the apertures in the sign panel so that they are held securely in place, not only against loosening and being accidentally dislodged, but also against attempted removal by vandals.

Heretofore it has been the practiceto provide the translucent member with a special mounting by which it is fastened in place, or to apply a separate fastening member to it after its insertion, or to form it with screw threads, a bayonet lock or the like, or to rely merely on friction. All of these modes of fastening are open to objection. Special mountings secured to the translucent member increase their cost substantially. Separate fastenings involve expense and additional labor in assembling. The other methods mentioned are unsatisfactory because they permit the member to be removed as easily as it is inserted and they also permit the members to become unintentionally loosened. Itis therefore a principal object of the invention toovervcome these objections byproviding for the autoand to form it at the same time that the aperture for receiving the translucent member is made,

thus effecting a saving in material, labor and time.

A still further object is to so form the translucent member as to effect a diffusion of light throughout an arc of at least so that it appears to be evenly and brilliantly illuminated over its entire area when viewed from a Wide range of positions and so that it will diffuse a substantial amount of light onto the face of the sign or other surface from which it protrudes.

With the foregoing and other objects in view, the present preferred embodiments of the invention will now be described in detail, in conjunction with the drawing in which:

Fig. l is a side elevation, in half-section, of one of the translucent elements taken'on the line Il of Fig. 2.

Fig. 2 is a plan view of the head cent element.

Fig. 3 is a section of a sheet-metal panel showing three modifications of the form of opening which is provided therein, in ac'cordance'with the invention, to effect automatic lockingin conjunction with the novel form of translucent element employed. l

Fig. 4 is a side elevation of a completely-installed translucent element, the metalpanel being shown in section.

Fig. 5 is a view similar angles thereto. I

Fig. 6 is a fragmentary view of an illuminated sign showing one manner of use of the translucent elements here involved.

The form of translucent element is best shown in Figs. 1 and 2. This element is preferably made from a transparent or translucent plastic, many suitable materials of this kind being known. It may be clear or in any desired color. The term "translucent is used hereinafter in its broad sense, to include transparent.

The material chosen should possess good thermostability, have a suificiently high impact strength to meet the requirements of the invention and should not be subject to excessive shrinking. It may be formed by molding or machining, and in the latter case it is not necessary that, it have a polished finish.

The light-emitting head 9, which is seen in plan in Fig. 2 is that portion of the element exof the transluto Fig. 4, takenat right tending above the panel in Figs. 4 and 5, and

vsides are provided with grooves l2 cut with their faces at an angle of about 90, one side of each groove being approximately parallel to the axis of the element and the other side parallel to the face I I. The grooves I2 are so spaced as to leave segments of the angular sides between them. The top face I I is provided with similar concentric 90 grooves I3, which are so formed, however, that their sides projected would form angles of 45 with the axis of the element.

I have determined experimentally that this form of head provides a Very high degree of dispersion of transmitted light, as indicated by the arrows, Fig. 4, giving the effect of high and evenly distributed luminosity. A substantial portion of the light is spread to the surface of the panel, which produces the desired effect of surface luminosity in the areas surrounding the elements.

The shank I4 of the element is of less diameter than the head portion, so as to provide a shoulder I5 which rests against the panel. The diameter of the shank decreases gradually toward the base I6 so that the shank is slightly tapered. The base I6 is of a slightly smaller diameter than the larger part of the shank which tapers to a diameter smaller than the base where it joins said base so as to provide a shoulder IT. The lower edge of the base is formed with an edge I8, beveled at about 45 to the axis, and a fiat face I9. I have found that with the form of head described, a flat face on the base provides the best distribution of light and I have further panel 26 behind which is a light source such as lamps 21' which may be augmented by reflecting surfaces 28. Light enters the translucent elements 25 through their base portions and their shanks. However, it has been found that the important light entering the shank is at such an angle that it produces substantially no luminosity of the head and that the effective light is almost entirely that which enters the face l9 and bevel I8 of the base I6. The relative formation of the base and head is therefore a matter of importance in producing the desired effect and not merely an arbitrary form.

The formation of the shank I l and base 16 also performs an important function in the fastening of the translucent element in a panel, which will now be described. Having provided elements possessing the essential features of a tapered shank and an enlarged base, both of which have substantially the same maximum diameters and form a shoulder at their junction, a sheetmetal panel 29 is perforated for their reception, as shown in Fig. 3. The perforating is done by any suitable punch designed to cut a hole of the size and shape of the largest part of the shank I4, this being the diameter of the shank where it joins the shoulder I5. This aperture is not cut out completely, however, but is so cut as to leave one or more integral inwardly extending tabs or projections. I have shown three modifications of such perforations: the hole 3i! iscut with two tabs 3|; the hole 32 has three tabs 33; and the hole 34 has four tabs 35. I have found two tabs to be suflicient but they may be increased or decreased in number as may be desired and dependme upon the thickness and nature of the metal,

the size and shape of the translucent element and other factors. It will of course be understood that the invention is not limited in use to a round element secured in a round hole but is equally adaptable to other shapes.

The translucent element is inserted and automatically locked in place in the metal panel 29 by merely forcing the element downwardly while centered over the aperture and resting on the tabs 3|, 33 or 35. The tabs are bent down by the pressure applied and, as a result of the inherent resiliency of the metal, engage with their ends the shoulder I! of the element. It will therefore be seen that in designing the element and the punch for cutting the holes they should be so proportioned that the bent tabs will correspond in length to the shank I4, thus causing the tips of the tabs to engage the shoulder I! so closely as to make a tight fit. It is not essential that the sheet metal be particularly springy, as this invention was designed for use with ordinary galvanized sheet material. Although such sheet is made of rather soft iron the amount of resiliency required is so slight, being only enough to move the tabs into contact with the face of shoulder II, that complete and instantaneous locking is satisfactorily effected.

In forcing the tabs 3|, 33 or 35 down by inserting the translucent element, the bevel or wellrounded edge I8 at the base of the translucent or light-transmitting element serves the very important function of so bending the tabs or projections upon the insertion of the element that their deformation starts gradually from the point near their free ends and proceeds gradually to the necessary degree, thus retaining the spring of the metal required for locking. If on the other hand these tabs should be bent by a relatively sharp edge contacting the tabs near their base they would be forced outward and away from the translucent element, which would defeat their purpose by not locking with the shoulder I'I. Apart from its effect on the light transmission, this edge might be rounded instead of beveled.

The invention has been described in conjunction with certain embodiments thereof selected only for purposes of illustration. Obvious modifications may be made therein without departing from the spirit of the invention, the scope of which is defined in the appended claims.

What is claimed is:

1. An element for transmitting light from a source behind a panel and presenting a brilliant glow on the face thereof, comprising a translucent body circular in cross-sections perpendicular to its axis and having a head to be disposed on the face of the panel and a shank to protrude through an aperture therein, said head being in the form of a, truncated cone having a plurality of circumferential grooves whose sides are approximately at right angles to one another and one of which is substantially parallel to the axis of said body, said shank terminating in a fiat face perpendicular to said axis.

2. An element according to claim 1 which is additionally provided with one or more concentric right-angle grooves in the face of said truncated cone, said grooves having one side at approximately 45 to said axis.

3. An element according to claim 1 in which the base of the shank is surrounded by a circumferential bevel.

' THOMAS V'EITCH. 

